1. Field of the Disclosure
The technology of the disclosure relates to fiber optic furcation plugs and assemblies for fiber optic cables, which may be used in securely mounting fiber optic cables in fiber optic equipment.
2. Technical Background
Optical fiber is increasingly being used for a variety of applications including but not limited to broadband voice, video, and data transmission. Benefits of optical fiber use include extremely wide bandwidth and low noise operation. With the increasing and varied use of optical fibers, it is important to provide reliable methods of routing optical fibers to subscribers. As a result, fiber optic communications networks include a number of interconnection points at which multiple optical fibers are interconnected. Fiber optic communications networks can readily extend fiber optic communications services to a subscriber. In this regard, fiber optic networks are being developed that deliver “fiber-to-the-curb” (FTTC), “fiber-to-the-business” (FTTB), “fiber-to-the-home” (FTTH) and “fiber-to-the-premises” (FTTP), referred to generically as “FTTx.”
In telecommunication infrastructure installations, including FTTx installations, fiber optic cables, such as trunk cables for example, are pulled to fiber optic equipment to establish optical connections. The fiber optic cables are furcated to separate out individual optical fibers for making optical connections with fiber optic components contained in the fiber optic equipment. The furcation is typically made in a furcation assembly, such as a furcation epoxy plug for example. To secure the fiber optic cable to fiber optic equipment and prevent it from being damaged or kinked, the furcation assembly is typically installed on the tray, rack, or housing of fiber optic equipment providing fiber optic components to which the optical fibers are connected.
When furcating a fiber optic cable to create a furcation assembly, a process called “break-out” or “fan-out” is provided. Optical fibers protected in a single fiber optic cable are made available to branch out in different directions to be terminated independent of one another. Break-out occurs at an end portion of the fiber optic cable where an outer jacket of the fiber optic cable is removed between an end of the fiber optic cable up to a transition point. The optical fibers are vulnerable to damage at the end portion of the fiber optic cable as they are no longer surrounded by the outer jacket nor protected from longitudinal and axial forces by strength members, which are strands of strong fibers that support the optical fibers in the fiber optic cable. The optical fibers at the end portion of the fiber optic cable are sometimes called “fiber legs.”
Conventional fiber optic furcation plugs provide for epoxy to be disposed inside the furcation body to bond the fiber optic furcation plug with strength members and optical fibers disposed in a fiber optic cable jacket. First, the fiber legs are inserted through a fiber optic furcation plug so that the transition point, a portion of the fiber legs adjacent to the transition point, and a portion of the cable jacket adjacent to the transition point are disposed within the fiber optic furcation plug. The fiber optic furcation plug is then sealed at the bottom where the outer jacket extends out of the furcation plug. Once the fiber optic furcation plug is positioned vertically so the bottom is facing down, an epoxy syringe is inserted down into the fiber optic furcation plug between the fiber legs of the fiber optic cable until an end of the epoxy syringe reaches the bottom portion of the fiber optic furcation plug. Next, epoxy is injected from the syringe into the bottom portion of the fiber optic furcation plug until the plug is filled. Finally the epoxy syringe is removed. When the epoxy is cured and forms a bond between the fiber legs, strength members, and fiber optic furcation plug, the fiber legs and the strength members may be securely attached to the fiber optic furcation plug. The fiber optic furcation plug may then be installed in an enclosure rack or patch panel and the fiber legs terminated.
Disposing epoxy in a fiber optic furcation plug by inserting the epoxy syringe into the fiber optic furcation plug between the fiber legs of the fiber optic cable may result in certain issues. First, the epoxy syringe could damage the optical fibers as the syringe is forced between the fiber legs. Also, the end of the epoxy syringe is difficult to precisely position when the syringe enters the fiber optic furcation plug because, for example, optical fibers and/or strength members may obstruct the path of the epoxy syringe. Precise positioning of the syringe is important to facilitate a uniform distribution of the epoxy within the fiber optic furcation plug; otherwise voids may form within the fiber optic furcation plug. These voids may change shape according to humidity and temperature, thereby causing unwanted attenuation in the adjacent fiber optic cables as they subject these adjacent fiber legs to expansion and contraction forces as they change shape. Further, as the voids are pockets of air, they may occupy volume that would ordinarily be taken up by strength-contributing epoxy, thereby weakening the attachment between the fiber optic furcation plug and the end portion of the fiber optic cable. If the fiber optic cable secured in the plug is subjected to an unexpected tension, as sometimes occurs as cables are installed or upgraded, then the fiber optic furcation plug may break.
Moreover, there is an increasing need for fiber optic furcation plugs to be provided in smaller sizes as installation requirements demand that fiber optic furcation plugs be pulled through smaller conduits at installation sites. As the fiber optic furcation plug is reduced in size, it may be more difficult to insert the epoxy syringe between the fiber legs and the passageway of the fiber optic furcation plug without damaging the optical fibers or misdirecting the epoxy syringe during the insertion of the epoxy.